A number of instruments are currently used for various forms of venepuncture and subcutaneous and intramuscular injection.
For example, a medical instrument commonly referred to as a "syringe" comprises a cylindrical receptacle carrying a piston, and a needle with a hub threadably mounted on an end of the receptacle. So mounted, the needle is fixed in place relative to the receptacle. The syringe is most often used for drawing blood and for providing subcutaneous and intramuscular injections.
Another medical instrument, termed a "vaccutainer," is primarily used to take multiple samples of blood. A syringe, as stated above, can also be used to sample blood. However, a syringe is only suited to draw a single sample of generally no more than 20 cc of blood. Oftentimes, it is necessary to take multiple blood samples, for example, when a multiplicity of blood tests must be performed on a patient. A vaccutainer can be used to take multiple blood samples upon a single puncture of the patient, thereby reducing patient stress which would otherwise result from the use of syringes and multiple punctures.
The vaccutainer includes a needle attached to a plastic receptacle. Both ends of the needle are exposed. One end is adapted to be inserted into a patient's vein. The other end is adapted to be inserted through a rubber stopper capping a vacuum-sealed glass tube. Upon insertion of the needle through the stopper, blood is drawn from the vein into the tube. When the tube is filled with blood, the tube is removed from engagement with the needle and replaced with another vacuum-sealed tube. In this manner, multiple sample tubes of a patient's blood may be obtained upon a single puncture.
In addition, an instrument known as a "butterfly needle" consists of a needle which is continuous at one end of the needle with a thin diameter rubber tubing. The tubing is adapted to be attached to a syringe, a vaccutainer tube, or any one of a variety of other collection receptacles. The free end of the needle is adapted to be inserted into a patient. The needle carries a plastic fitting having a pair of oppositely projecting "wings" for use in guiding the needle, hence the name "butterfly." The butterfly needle and its associated tubing and receptacle are most often used for collecting blood.
A further example of a medical instrument, termed an "I.V. (intravenous) catheter" is generally used for administering replacement fluids, such as saline solutions, lactated ringer's solution, dextrose water solutions and blood by transfusion.
The I.V. catheter consists of an I.V. placement unit comprising a needle having permanently affixed on one end thereof a plastic handle. A thin plastic sheath having its own plastic handle slidably receives the needle. The sheath extends substantially the entire length of the needle. In use, once the needle with surround sheath have been inserted into a patient's vein, the needle is removed, leaving the sheath behind inside the vein. The needle with its handle is then discarded. A line of rubber tubing is mounted on the handle of the sheath, the free end of the rubber tubing being connected to an I.V. bag.
Although the above-described medical instruments may be effective for performing various forms of venepuncture and subcutaneous and intra-muscular injections, they are associated with a common disadvantage. The problem arises from the lack of a safe and effective method of needle removal and disposal, a problem with which medical institutions, medical personnel, waste disposal personnel and others have become acutely aware as a result of the relatively recent heightened publicity surrounding Hepatitis and the uniformly-fatal disease, "Aquired Immune Deficiency Syndrome (AIDS)."
Several methods of needle disposal are currently used in medical environments, none of which have been demonstrated as being sufficiently safe for medical personnel and waste removal workers, as each of these methods may result in inadvertent contact or puncture by a contaminated needle.
One method of contaminated need disposal requires transportation of, for example, a syringe with attached contaminated needle to a cardboard "needle box" and cutting the needle over the box with a clipper to thereby detach the needle from the syringe proper, the needle then dropping into the box. This method has been demonstrated to be ineffective due to the danger of micro-aerosol spray when the needle is clipped. Moreover, there exists an inherent danger in carrying the exposed needle to the box, as well as disposing of a box filled with contaminated needles. In addition, contaminated needles invariably slip out of the box through seams at folded edges of the paperboard box, and thus present a further danger.
Other dirty needle boxes are currently used. For example, a plastic bucket with hinged lid is commonly in use. Although use of this box eliminates the possibility of leakage of contaminated needles from the box, as there are no open seams through which the needles can pass. However, the inherent dangers associated with carrying needles to the box and micro-aerosol spray (if needles are cut) remain.
Other methods of disposing of contaminated needles consist of either (1) throwing the entire syringe or other like medical instrument with the needle attached thereto into a needle box, or (2) recapping the needle, removing it from the syringe proper, and throwing it into a box. The latter method is the most dangerous. However, in either case, transporting a capped or uncapped needle to a designated container has proven to be both cumbersome and a constant health hazard to both medical institutions and medical and other personnel.
Further, needles are inadvertently thrown into regular waste bins. This poses a constant danger to housekeeping personnel as well as contributing to increased insurance costs of medical institutions.
Therefore, it is obvious that, until the use of needles becomes obsolete, methods and devices directed to reducing the likelihood of inadvertent contact with contaminated needles must be developed.
It has thus been desirable to provide a medical instrument of the type described below in detail comprising a needle which is retractable with respect to the medical instrument so as to reduce the likelihood of accidental contact of personnel with the needle after its use.